CN101207950A - Driving method and system of light emitting diode and redundant circuit - Google Patents

Abstract

The present invention is a light emitting diode (LED) driving system and method, which is used to drive the light emitting diode to emit light continuously and stably. It mainly uses a DC voltage source circuit to supply DC power to the light emitting diode, and through a constant voltage and constant current regulator, it can efficiently use AC power including household power to drive the light emitting diode to emit light continuously and at a constant power, so that multiple light emitting diodes can still be driven by the same driver to maintain the same constant power light emission performance.

Description

Driving method, system and redundant circuit of light emitting diode

technical field

The present invention relates to a light emitting diode (Light Emitting Diode, LED) drive system and method, especially to a light emitting diode that can be used to drive stable light, and is not limited to special process technology to maintain good light emitting characteristics A driving system and method for a light emitting diode.

Background technique

The principle of action of a light-emitting diode is to flow current forward into the p-n interface of the semiconductor, so that the electrons on the interface combine with the holes to generate energy and emit it in the form of light; therefore, the luminance of the light-emitting diode and the current flowing through it are proportional, that is The higher the input current, the higher the luminous brightness. The traditional LED driving method is nothing more than adopting constant voltage ( FIG. 10A ), constant current ( FIG. 10B ), or alternating current ( FIG. 10C ) to drive the LED to generate forward bias current to emit light. Among them, the constant voltage driving method is to use a resistor 91 connected in series with the light-emitting diode to control the current value flowing through the series line. As long as the voltage value of the voltage source input to the light-emitting diode is fixed, the effect of constant current will be achieved. This driving method is the largest Disadvantages Even a slight change in the power supply voltage will be affected, so a stabilized power supply must be used. In addition, the heat generation of the light-emitting diode itself and the change in the luminous characteristic relationship (I-V correlation curve) caused by changes in the surrounding temperature must be considered; The constant current driving method is to use a current source 92 connected in series with the LED. The fixed current source can make the current flowing through the LED more stable against weak power voltage fluctuations. However, it is still necessary to be careful that the LED itself is affected by external factors to luminous characteristics. The relationship (I-V correlation curve) is changed; the AC drive method is to use an AC voltage source to drive the light-emitting diode. In order to drive the forward bias current, it is necessary to place a diode 93 in the same forward direction as the light-emitting diode to limit the passage of the DC voltage. At the same time, a capacitor connected in parallel with the light-emitting diode is used to make the input DC voltage fluctuate less, so as to generate a less fluctuating light-emitting diode current, and the AC drive is used to make the voltage source easier to obtain from the household power supply, but the fluctuation of the AC voltage source is different from that of the household power supply. The voltage surge is more likely to cause the current of the LED to fluctuate and even cause damage to the LED.

Due to the high luminance and multi-color of light-emitting diodes in recent years, the application of light-emitting diodes has gradually expanded to display light sources, aviation guidance lights, light-emitting diode backlighting modules, signal lamps, display panels and other fields. In the future, it may even be possible It is hoped to replace fluorescent lamps as the main lighting source; therefore, the driving technology of light-emitting diodes is no longer just driving light-emitting diodes to emit light. In addition to the miniaturization of the driving circuit, it should also have high stability, high efficiency, multiple lights, And can make the battery to extend the use of time and other characteristics. However, whether it is constant voltage drive, constant current drive, or AC drive, it still cannot provide a stable drive current that is not affected by voltage fluctuations or even voltage surges; in addition, when connecting more and more light-emitting diodes, these In light-emitting diodes, there will be some errors in the light-emitting characteristic relationship (I-V correlation curve) due to the mass-manufacturing process, so that the same driving circuit design cannot be applied to all light-emitting diodes in mass production, resulting in an increase in mass production costs. Or the sacrifice of luminous stability.

Contents of the invention

The object of the present invention is to provide a driving system and method of light emitting diodes and a redundant circuit, to simultaneously lock the voltage and current, to provide high-quality constant power light emitting diode drive; and because it can provide stable driving, so that multiple The light-emitting diodes can still be driven by the same driver, which saves wiring space but still maintains the fixed total luminous power of the multiple light-emitting diodes; together with the AC-DC rectifier or DC-to-DC converter circuit to supply DC power, it can Let the driven light-emitting diode group emit light continuously and with a fixed power.

In order to achieve the above object, the technical solution adopted by the present invention lies in a method for driving a light-emitting diode (LED) to provide light-emitting diodes with a constant power, comprising the following steps: step a: outputting a DC power supply by a DC voltage source circuit;

Step b: pressurizing the DC voltage to a light-emitting diode group to generate a current flowing through the light-emitting diode group to make the light-emitting diode group emit light;

Step c: The current flowing through the LED group is then passed through a constant voltage and constant current adjustment step, so that the current flowing through the LED group is stabilized as a fixed current, and the voltage drop of the LED group is stabilized as a fixed voltage.

In order to achieve the above purpose, the technical solution adopted by the present invention is to provide a driving system for light emitting diodes for the light emitting diodes to emit light at a constant power, and the driving system includes:

Step a: a DC voltage source circuit, which converts the input AC voltage into a DC voltage;

Step b: A LED group is connected to the DC voltage output by the DC voltage source circuit to generate a current flowing through the LED group;

Step c: a constant voltage and constant current regulator to make the current flowing stably through the light emitting diode group be a constant current, and stabilize the voltage drop of the light emitting diode group to be a constant voltage.

In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a redundant circuit for use in a light-emitting diode group, which detects that the voltage difference between any two nodes in the light-emitting diode group exceeds the start-up voltage, That is, the redundant controller is started to control the bypass circuit of the two nodes to be in a conducting state, so that the current of the LED group can bypass the abnormally operating LEDs between the two nodes, so as to maintain the light emitting diodes The diode set glows normally.

In order to make the above-mentioned contents, objectives, advantages and other features of the present invention more comprehensible, the present invention will be described in detail below in conjunction with the drawings and preferred embodiments.

Description of drawings

FIG. 1 is a structural diagram of the driving system and method of the present invention.

Figure 2 is an explanatory diagram of the constant current circuit method.

Fig. 3 is a diagram of the first embodiment of the drive system of the present invention.

Fig. 4 is a diagram of the second embodiment of the drive system of the present invention.

Fig. 5 is a diagram of an embodiment of a current source in the drive system of the present invention.

Fig. 6A is a diagram of the first embodiment of the current sink in the drive system of the present invention.

Fig. 6B is a diagram of the second embodiment of the current sink in the drive system of the present invention.

Fig. 6C is a diagram of the third embodiment of the current sink in the drive system of the present invention.

FIG. 7A is an embodiment of an all bridge rectifier used in the driving system of the present invention.

Fig. 7B is the first embodiment of the full bridge rectifier in the driving system of the present invention.

FIG. 7C is a second embodiment of the all bridge rectifier in the driving system of the present invention.

FIG. 7D is a third embodiment of the all bridge rectifier in the driving system of the present invention.

FIG. 7E is a fourth embodiment of the all bridge rectifier in the driving system of the present invention.

FIG. 8A is an embodiment of a half bridge rectifier used in the drive system of the present invention.

FIG. 8B is a first embodiment of a half bridge rectifier in the drive system of the present invention.

FIG. 8C is a second embodiment of the half bridge rectifier in the driving system of the present invention.

FIG. 8D is a third embodiment of the half bridge rectifier in the driving system of the present invention.

Fig. 9A is a schematic diagram of redundant circuit (redundancy) configuration in the drive system of the present invention

Figure 9B is a diagram showing the variation of the current of the silicon controlled rectifier (SCR) with the voltage (I-Vcurve)

Fig. 9C is a diagram showing a first embodiment of the bypass circuit in Fig. 9A

Figure 9D is a diagram showing a second embodiment of the bypass circuit in Figure 9A

Figure 9E is a diagram showing a third embodiment of the bypass circuit in Figure 9A

Figure 9F is a diagram showing a fourth embodiment of the bypass circuit in Figure 9A

Fig. 9G is a diagram showing a fifth embodiment of the bypass circuit in Fig. 9A

Figure 9H is a diagram showing a sixth embodiment of the bypass circuit in Figure 9A

FIG. 10A is a schematic diagram of a constant voltage driving method in the background technology.

FIG. 10B is a schematic diagram of a constant current driving method in the background technology.

FIG. 10C is a schematic diagram of an AC driving method in the background technology.

Explanation of reference signs: 110-DC voltage source circuit; 120-light-emitting diode group; 111, 1111-1117-AC-DC rectifier; 130-constant voltage and constant current adjustment step; 131-constant voltage and constant current adjustment step output terminal; 132- Constant voltage circuit; 133-constant current circuit; VAC-AC voltage; VDC-DC voltage; VLED_DC-voltage output by DC voltage source circuit; VLED-voltage drop at both ends of the LED group; ILED-LED group current; Vref- The reference voltage of the constant voltage circuit; Vf-the output voltage of the constant voltage circuit; Vset-the setting voltage of the current source; Rset-the setting resistance of the current source; Von_off-the switching transistor gate voltage of the current sink; Iref-the current source 230-constant voltage and constant current regulator; 231-constant voltage and constant current regulator output terminal; 232-constant voltage circuit; 2321-constant voltage circuit output terminal; 2322-constant voltage circuit positive input terminal; 2323 -gain output terminal of constant voltage circuit; 2324-constant voltage operational amplifier 233-constant current circuit; 234-current source; 2341-current source first output terminal; 2342-current source second output terminal; 2343-current The positive input terminal of the source; 235-current sink; 2351-the first input terminal of the current sink; 2352-the second input terminal of the current sink; 236-the constant voltage transistor of the first embodiment; 237-the second embodiment Constant voltage transistor; Vf1-the output terminal voltage of the constant voltage circuit; Vf2-the second output terminal voltage of the current source; 510-the operational amplifier for constant current; 511-the transistor for constant current; 512-the positive carrier channel current mirror; 611-the first current mirror; 612-the second current mirror; 613-the common gate transistor of the current sink; 614-the transistor switch of the third embodiment of the current sink; 71-the bypass circuit of the redundant circuit; 72-the redundant circuit Redundant controller; IG-the gate current output from the redundant controller to the bypass circuit; VG-the gate voltage output from the redundant controller to the bypass circuit; 1stMOSFET-the first metal oxide semiconductor field effect transistor; 2ndMOSFET-the second Two metal-oxide-semiconductor field-effect transistors; 91—resistor in the background technology of constant voltage driving mode; 92—current source in the background technology of constant current driving mode; 93—diode in the background technology of AC driving mode.

Detailed ways

The above and other technical features and advantages of the present invention will be described in more detail below in conjunction with the accompanying drawings.

Fig. 1 is the diagram of the first embodiment of the driving method of the light-emitting diode of the present invention, which is mainly divided into three steps, wherein the first step is that a DC voltage source circuit 110 outputs a DC power supply VLED_DC; the second step is to convert the DC voltage VLED_DC is pressurized to a light emitting diode group 120 to generate a current ILED flowing through the light emitting diode group to make the light emitting diode group emit light. The light emitting diode group is a single light emitting diode, or a plurality of light emitting diodes are connected in series to form a light emitting diode string and the third step is a constant voltage and constant current adjustment step 130, which stabilizes the current ILED flowing through the light-emitting diode group into a fixed current through this step, so that the fixed current is not affected by voltage fluctuations, And the voltage drop of the light emitting diode group is stabilized to a fixed voltage, so that the voltage drop of the light emitting diode group is not affected by temperature and other factors that change the luminous characteristics. The described constant voltage and constant current regulation step is shown in Figure 1, comprises the following steps: has an output end 131, accepts the electric current ILED from described light-emitting diode group; And locks described constant voltage by a constant voltage circuit 132 The voltage Vf of the circuit output terminal, the output terminal of the described constant voltage circuit is connected to the output terminal of the described constant voltage and constant current adjustment step, to stabilize the output terminal voltage of the constant voltage and constant current adjustment step, and consume unnecessary voltage fluctuations; by a constant voltage and constant current adjustment step. The current circuit 133 is connected to the current ILED of the LED set passing through the constant voltage circuit to lock the current ILED of the LED set to a set current amount. Through the constant voltage and constant current adjustment step, the current flowing through the light-emitting diode group can be stabilized as a fixed current without being affected by voltage fluctuations, and at the same time, the voltage drop of the light-emitting diode group can be stabilized to a fixed voltage, so that the voltage drop of the light-emitting diode group is not affected by temperature. And other factors that change the luminous characteristics. In the constant voltage circuit, a reference voltage Vref can also be used to adjust and set the voltage Vf at the output terminal of the constant voltage step.

Please refer to FIG. 2 , in the constant current circuit 133, a set voltage Vset and a set resistor Rset can also be used to make the set resistor Rset limit the maximum output current Iref, and the set voltage Vset can adjust the set value. The current Iref output by the above-mentioned reference current source, in addition to this, a functional (functional) gate voltage is used to set the light-emitting switch of the light-emitting diode group, and at the same time, the flicker frequency of the functional light is to achieve the desired of luminous power.

The first implementation method of the DC voltage source circuit includes: an AC transformer circuit inputs an AC voltage source VAC, and an AC/DC rectifier circuit (AC/DC rectifier) converts the AC voltage source VAC into a DC voltage source VDC , and finally through a DC-to-DC conversion circuit (DC/DC converter), the above-mentioned DC voltage source VDC with large fluctuations is converted into an output DC voltage source VLED_DC with small fluctuations, so that AC power sources including household power sources can be directly Input a DC voltage source circuit to output a DC voltage VLED_DC. Among them, before entering the AC-DC rectification circuit, one or more voltage doubler circuits can also be added to multiply the voltage value of the AC voltage source VAC once or more times, so that the household power supply can be used more flexibly to drive the light diode. The second implementation method of the DC voltage source circuit includes: the DC voltage source VLED_DC output by the DC voltage source circuit is output by another DC voltage VDC via a DC/DC converter circuit (DC/DC converter). The DC voltage source VLED_DC. The third implementation method of the DC voltage source circuit includes: an AC-DC rectifier circuit converts VAC to a DC voltage source VLED_DC, so that AC power including household power can be directly input into the DC voltage source circuit to output a DC voltage VLED_DC.

In the implementation process, it is inevitable that some light-emitting diodes will not operate normally due to some external factors or accidental conditions. The light emitting diode group can emit light normally without being affected. The redundant circuit detects that the voltage difference between any two nodes (nodes) in the LED group exceeds the start-up voltage Vth, so as to start a redundant controller (redundancy control) 72 to control the detour of the two nodes The circuit 71 is in a conducting state, so that the current ILED of the LED group can bypass the abnormally operating LED between the two nodes, so as to maintain the normal light emission of the LED group. The start-up voltage Vth can be a fixed value or a modulated value.

FIG. 3 is a diagram of the first embodiment of the LED driving system of the present invention, which is mainly divided into three parts, wherein the first part is a DC voltage source circuit 110 . Figures 7A-7E and Figures 8A-8D disclose more embodiments of DC voltage source circuits using the AC-DC rectifier 111, Figures 7A-7E disclose full-bridge (allbridge) rectifiers 1111-1114, Figures 8A-8D The half-bridge rectifiers 1115-1117 are disclosed, the purpose of which is to convert the AC voltage source VAC into the DC voltage source VLED_DC available for the second part of the light-emitting diode group shown in FIG. Power supply to drive LED groups. The LED current ILED generated by the DC voltage source VLED_DC pressurizing the LED group then enters the third part of the constant voltage and constant current regulator 230 shown in FIG. 3 , and the current flowing stably through the LED group 120 is Fix the current, so that the fixed current is not affected by voltage fluctuations; and stabilize the voltage drop VLED of the light-emitting diode group to a fixed voltage, so that the voltage drop of the light-emitting diode group is not affected by temperature and other factors that change the luminous characteristics; thus, the light-emitting diode The total luminous power of the group PLED=ILED*VLED, wherein ILED is fixed and VLED is also fixed, so the total luminous power PLED is also fixed.

The working principle of the constant voltage and constant current regulator 230 controlling current and voltage will be described with reference to FIG. 3 . It includes: an output terminal 231 of a constant voltage and constant current regulator, which receives the current ILED from the light-emitting diode group; a constant voltage circuit 232 locks the voltage Vf1 of the output terminal of the constant voltage circuit for stable constant voltage and constant current The output terminal 231 voltage of the device 230; and a constant current circuit 233 is connected to the current ILED of the light-emitting diode group passing through the constant voltage circuit 232, for locking the current ILED of the light-emitting diode group to a set current amount There is also a constant voltage transistor (transistor) 236, which is connected in series with the light emitting diode group 120 and the constant current circuit 233. Wherein, the constant voltage circuit is a constant voltage operational amplifier (operation amplifier) 2324, its positive input terminal is connected to a reference voltage Vref provided by a band gap reference voltage (band gap reference voltage), its negative input terminal Connect Vf1, and form a negative feedback (feedback) circuit through the transistor for constant voltage, which can stably lock the voltage Vf1 of the output terminal of the voltage regulator, and consume the excess voltage drop to the transistor for constant voltage. Stabilize the voltage drop VLED of the light-emitting diode group; here, the effect of the transistor for constant voltage is equivalent to a variable resistor, therefore, the transistor 236 for constant voltage can also be placed on another part of the light-emitting diode group One end is the constant voltage transistor 237 in Figure 4, which is placed between the DC voltage source circuit and the light-emitting diode group, and the gain output end of the operational amplifier 2324 for the constant voltage is connected to the constant voltage. The gate of the voltage transistor 237 forms a negative feedback (feedback) circuit through the constant voltage transistor, and also completes the consumption of excess voltage drop to stabilize the voltage drop VLED of the LED group.

To complete the working principle of the constant voltage and constant current regulator 230 controlling current and voltage, a constant current circuit 233 is required to be composed of a current source (current source) 234 as shown in Figure 5, and a current sink (current sink) 235, as shown in the figure 6A-6C. Wherein the first embodiment of the current source 234 includes: an operational amplifier 510 for constant current, its positive input terminal is connected to the positive input terminal 2343 of the current source and a set voltage Vset is provided by a bandgap reference voltage, Its negative input terminal is connected to the second output terminal 2342 of the current source, and its gain output terminal is connected to its negative input terminal to form a negative feedback (feedback) circuit for stably locking the second output terminal of the current source Voltage Vf2 and the voltage Vf2 of the second output terminal is pressurized to the set resistor Rset to generate a current flowing out of the second output terminal; and a positive carrier channel (pchannel) current mirror (current mirror) 512, the The positive carrier channel current mirror is composed of a pair of common gate positive carrier channel transistors, and the drain of one of the positive carrier channel transistors is connected to the gate, which is the input terminal of the positive carrier channel current mirror. , and the drain of another positive carrier channel transistor is the output terminal of the positive carrier channel current mirror, and the input terminal of the positive carrier channel current mirror is connected to the second of the current source The output terminal, the output terminal of the positive carrier sub-channel current mirror is connected to the first output terminal 2341 of the current source to copy the current flowing out of the second output terminal to output the reference current Iref.

Referring to Fig. 5, the second embodiment of the current source is the circuit of the first embodiment plus a constant current transistor 511 placed on the second output terminal of the current source and the fixed positive carrier channel current Between the input terminals of the input terminal of the mirror, and between the gain output terminal of the operational amplifier for constant current and the negative input terminal, the connection is cut off and connected to the gate of the transistor for constant current, so as to strengthen and stabilize the The voltage fluctuation at the second output terminal of the current source absorbs the excess voltage drop in the current source.

Wherein the first embodiment of the current sink, as shown in FIG. 6A, is a first current mirror (current mirror) 611. The first current mirror 611 is composed of a pair of common gate transistors, and the drain of one of the transistors Connected with the gate, it is the input terminal of the first current mirror, and the drain of the other transistor is the output terminal of the first current mirror, and the input terminal of the first current mirror is connected to the The first input end 2351 of the current sink is connected to the reference current Iref output from the first output end 2341 of the current source, and the output end of the first current mirror is connected to the second input end of the current sink 2352 connection, for connecting the current ILED from the light-emitting diode group, and stabilizing the voltage of the second input terminal of the power supply slot through the constant voltage circuit, and at the same time, the first current mirror uses the The reference current Iref output by the current source is used to lock and amplify the LED group current ILED by N times the reference current Iref, and the N times value N=ILED/Iref, wherein N is a set fixed value.

The second embodiment of the current sink is shown in FIG. 6B, a second current mirror 612 identical to the first current mirror, and the input end of the second current mirror is interposed between the input end of the first current mirror and the first current mirror. Between the first input terminal 2351 of the current sink, the reference current Iref output from the first output terminal of the current source is connected, and the output terminal of the second current mirror is between the first current mirror Between the output terminal and the second input terminal 2352 of the current sink, the current ILED from the light-emitting diode group is connected, and the second current mirror is the same as the first current mirror, with the current The source outputs the reference current Iref to lock the light-emitting diode group current ILED that is amplified by N times the reference current Iref, and the N times value N=ILED/Iref.

The third embodiment of the current sink is shown in FIG. 6C , a pair of current sink common gate transistors 613 are placed between the first current mirror and the input terminal of the current sink, and the pair of current sink common The gate of the gate transistor is connected to the line and a transistor switch 614 is added, and the gate voltage of the transistor switch is used to control the switch of the current of the light-emitting diode group, and at the same time, the functionalized (functional) transistor switch The gate voltage modulates the flickering frequency of the light-emitting diode group to achieve the expected AC luminous power.

The above-mentioned DC voltage source circuit 110 includes an AC/DC rectifier (AC/DC rectifier) or a DC-to-DC converter (DC/DC converter), which supplies the DC voltage source VLED_DC required by the light-emitting diodes; the light-emitting diode group 120 It is composed of more than one light-emitting diode; in practice, the light-emitting diode group 120 is a series of light-emitting diodes connected in series. The light-emitting diode group 120 can also be a plurality of light-emitting diodes connected in series and then connected in parallel (not shown in the figure); the constant voltage and constant current circuit 130, when the DC voltage VLED_DC fluctuates, the constant voltage circuit 232 stabilizes the light-emitting diodes The voltage drop VLED, and the constant current circuit 233 makes the current (ILED) 133 passing through the LED group 120 a constant current to achieve the desired constant power (power=VLEDxILED).

FIG. 9A is a schematic diagram of redundant circuit configuration, and the redundant circuit includes a bypass circuit 71 connected in parallel with light emitting diodes and a redundant controller 72 . Figure 9C shows that the first embodiment of the bypass circuit is a silicon controlled rectifier (silicon controlled rectifier, SCR) connected in parallel with the light emitting diode group, and the gate of the silicon controlled rectifier is controlled by a redundant controller, when The redundant controller outputs the gate current IG to turn on the silicon controlled rectifier device so that the light emitting diode current ILED bypasses the abnormally operating light emitting diode. Its working method is as shown in FIG. 9B , which shows the I-V curve of the silicon controlled rectifier component current changing with the voltage (I-V curve), and it can turn on the current after the overvoltage event occurs to avoid the abnormal operation of the light emitting diode.

Fig. 9D shows that the second embodiment of the bypass circuit includes: a first metal-oxide-semiconductor field-effect transistor (1stMOSFET) connected in parallel with the light-emitting diode group, and the gate of the first metal-oxide-semiconductor field-effect transistor is formed by The redundant controller controls, when the redundant controller outputs the gate voltage VG, it turns on the first metal-oxide-semiconductor field-effect transistor so that the light-emitting diode current ILED bypasses the abnormally operating light-emitting diode; and a connection to the The resistors of the drain and the gate of the first MOSFET are used to set the set voltage Vth value of the redundant circuit. At the same time, it also includes a resistor connected in series with the source of the first metal-oxide-semiconductor field effect transistor to match the conduction current value of the bypass circuit to lock the voltage difference after the bypass circuit is turned on value.

FIG. 9E shows that the third embodiment of the bypass circuit includes: a zener diode connected in parallel with the light-emitting diode group. When the voltage across the bypass circuit exceeds the set voltage Vth value due to the abnormal operation of the light-emitting diode, The reverse bias (reverse bias) current of the Zener diode starts to conduct, so that the light-emitting diode current ILED bypasses the abnormally operating light-emitting diode; and the resistor connected in series with the reverse bias voltage set inside the Zener diode value and current value to set the set voltage Vth value of the redundant circuit, and at the same time, the voltage difference of the bypass circuit after it is turned on is also locked with the internal setting of the all-sodium diode.

Fig. 9F shows that the fourth embodiment of the bypass circuit is to change the resistance connected in series with the source of the first metal-oxide-semiconductor field-effect transistor in the second embodiment to a Zener diode (zener diode), and at the same time, the bypass circuit is The voltage difference after conduction is also locked with the internal setting of the all-sodium diode.

Figure 9G shows that the fifth embodiment of the bypass circuit is to change the resistor connected in series with the source of the first MOSFET in the second embodiment to a second MOSFET connected to the drain. At the same time, the voltage difference of the bypass circuit after it is turned on is also locked because the second metal oxide semiconductor field effect transistor locks the current in the active region (active region).

Figure 9H shows that the sixth embodiment of the bypass circuit includes: a transistor (transistor) connected in parallel with the light emitting diode group, and the gate of the transistor is controlled by the redundant controller, when the redundant controller outputs the gate current IG Then turn on the transistor so that the light-emitting diode current ILED bypasses the abnormally operating light-emitting diode, and the redundant controller also controls the base current (base current) for setting the bypass circuit to be turned on the final voltage difference; and a resistor connected to the drain and gate of the first metal-oxide-semiconductor field-effect transistor for setting the set voltage Vth value of the redundant circuit.

To sum up, according to the diagrams and descriptions disclosed above, the present invention can achieve the expected purpose, providing a system and method for driving LEDs with high quality and constant power, which can simultaneously lock the voltage and current, and can be used in industries.

The above descriptions are only preferred embodiments of the present invention, and are only illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims (40)

1. A driving method of a light-emitting diode, for light-emitting diodes with constant power, characterized in that: the driving method comprises the following steps: Step a: outputting DC power from a DC voltage source circuit; Step b: pressurizing the DC voltage to a light-emitting diode group to generate a current flowing through the light-emitting diode group to make the light-emitting diode group emit light; Step c: The current flowing through the LED group is then passed through a constant voltage and constant current adjustment step, so that the current flowing through the LED group is stabilized as a fixed current, and the voltage drop of the LED group is stabilized as a fixed voltage. 2. The driving method according to claim 1, characterized in that: said step of adjusting constant voltage and constant current further comprises the following steps: Step a: having an output terminal for receiving the current from the LED group; Step b: A constant voltage circuit is used to lock the voltage of an output terminal of the constant voltage circuit, and the output terminal of the constant voltage circuit is connected to the output terminal of the constant voltage and constant current adjustment step to stabilize the constant voltage and constant current adjustment Step output voltage, consume excess voltage fluctuations; Step c: connecting the current ILED of the light emitting diode group through the constant voltage circuit through a constant current circuit to lock the current of the light emitting diode group to a set current amount. 3. The driving method according to claim 2, characterized in that: said step of adjusting constant voltage and constant current further comprises the following steps: Step a: outputting a stable reference current from a reference current source; Step b: receiving the reference current output by the reference current source, and locking the current of the LED group according to the reference current. 4. The driving method according to claim 2, characterized in that: said step of adjusting constant voltage and constant current further comprises: adjusting and setting the voltage at the output terminal of said constant voltage circuit by a reference voltage. 5. The driving method according to claim 3, characterized in that: said constant voltage and constant current adjusting step further comprises: adjusting and setting said reference current source output by a set voltage and a set resistance current. 6. The driving method according to claim 3, characterized in that: said step of adjusting constant voltage and constant current further comprises: using a functionalized gate voltage to set the light-emitting switch of said light-emitting diode group, the function Optimize the flashing frequency of the luminescence to achieve the expected luminous power. 7. The driving method according to claim 1, characterized in that: said light emitting diode group is a single light emitting diode. 8. The driving method according to claim 1, characterized in that: the light emitting diode group is a plurality of light emitting diodes connected in series to form a light emitting diode string. 9. The driving method according to claim 1, characterized in that: the DC voltage source circuit comprises: an AC transformer circuit input AC voltage source; an AC-DC rectifier circuit converts the AC voltage source into DC Voltage source; then through a DC to DC conversion circuit, the DC voltage source with large fluctuations is converted into an output DC voltage source with small fluctuations, so that the AC power including household power can be directly input into the DC voltage source circuit for output DC voltage. 10. The driving method according to claim 9, characterized in that: said DC voltage source circuit further comprises: one or more voltage doubler circuits convert the voltage value of said AC voltage source before entering the AC/DC rectifier circuit Multiplied one or more times. 11. The driving method according to claim 1, wherein the DC voltage source output by the DC voltage source circuit is output from another DC voltage via a DC-to-DC conversion circuit. 12. The driving method according to claim 1, characterized in that: the DC voltage source is converted into a DC voltage source through an AC-DC rectifier circuit from the input AC voltage source, so that the AC power source including the household power supply can be Directly input DC voltage source circuit to output DC voltage. 13. A driving system for light-emitting diodes, for light-emitting diodes to emit light at a constant power, characterized in that: the driving system includes: Step a: a DC voltage source circuit, which converts the input AC voltage into a DC voltage; Step b: A LED group is connected to the DC voltage output by the DC voltage source circuit to generate a current flowing through the LED group; Step c: a constant voltage and constant current regulator to make the current flowing stably through the light emitting diode group be a constant current, and stabilize the voltage drop of the light emitting diode group to be a constant voltage. 14. The drive system according to claim 13, characterized in that: said constant voltage and constant current regulator further comprises: Step a: an output terminal receiving the current from the LED group; Step b: A constant voltage circuit locks the voltage at the output terminal of the constant voltage circuit, wherein the output terminal of the constant voltage circuit is connected to the output terminal of the constant voltage and constant current regulator to stabilize the output of the voltage and constant current regulator terminal voltage; Step c: A constant current circuit is connected to the current of the LED group passing through the constant voltage circuit to lock the current of the LED group to a set current amount. 15. The driving system according to claim 14, characterized in that: said constant voltage and constant current regulator further comprises: Step a: a current source, including a first output terminal, which outputs a stable reference current Iref; Step b: a current sink, which includes: a first input terminal receiving the reference current Iref output by the first output terminal of the current source; and a second input terminal connected to the output terminal of the constant voltage circuit, Taking the current ILED connected to the light emitting diode group and locking the current ILED according to the reference current Iref as a set current amount, ILED=Iref*N, where N is a set fixed value. 16. The drive system according to claim 14, characterized in that: said constant voltage and constant current regulator further comprises: a positive input terminal for inputting a reference voltage for adjusting and setting the voltage at the output terminal of said constant voltage circuit . 17. The driving system according to claim 15, characterized in that: said constant voltage and constant current regulator further comprises: a positive input terminal for inputting a set voltage Vset for adjusting and setting the output terminal of said current source voltage Vf2; and a setting resistor connected between the second output terminal of the current source and the ground terminal for adjusting and setting the output current Iref=Vf2/Rset of the first output terminal of the current source. 18. The driving system according to claim 13, characterized in that: said light emitting diode group is a single light emitting diode. 19. The drive system according to claim 13, characterized in that: said light emitting diode group is a plurality of light emitting diodes connected in series to form a light emitting diode string. 20. The drive system according to claim 13, characterized in that: said DC voltage source circuit comprises: an AC transformer circuit input AC voltage source; an AC-DC rectifier circuit converts said AC voltage source into DC Voltage source; then through a DC to DC conversion circuit, the DC voltage source with large fluctuations is converted into an output DC voltage source with small fluctuations, so that the AC power including household power can be directly input into the DC voltage source circuit, so as to output DC voltage. 21. The drive system according to claim 20, characterized in that: the DC voltage source circuit further comprises: one or more voltage doubler circuits to convert the voltage value of the AC voltage source before entering the AC/DC rectifier circuit Multiplied one or more times. 22. The driving system according to claim 13, characterized in that: the DC voltage source output by the DC voltage source circuit is another DC voltage outputting the DC voltage source through a DC-to-DC converter circuit. 23. The driving system according to claim 13, characterized in that: said DC voltage source is converted from an input AC voltage source to a DC voltage source through an AC-DC rectifier, so that AC power including household power can be directly input A DC voltage source circuit to output a DC voltage. 24. The drive system according to claim 16, characterized in that: said constant voltage and constant current regulator further comprises: a transistor for constant voltage, placed between the output terminal of said constant voltage circuit and said constant voltage between the input terminals of the voltage constant current regulator; and an operational amplifier for constant voltage, wherein the positive input terminal of the operational amplifier for constant voltage is connected to the positive input terminal of the constant voltage circuit and connected to the reference voltage , the negative input end of which is connected to the output end of the constant voltage circuit, and the gain output end is connected to the gate of the transistor for constant voltage, and a negative feedback circuit is formed by the transistor for constant voltage, wherein the The reference voltage is a bandgap reference voltage, which is used to lock the voltage of the output terminal of the constant voltage circuit, and consume excess voltage drop to the transistor for constant voltage to stabilize the voltage drop of the LED group. 25. The drive system according to claim 16, characterized in that: it further comprises a transistor for constant voltage, placed between said DC voltage source circuit and said light-emitting diode group; and wherein said constant voltage The constant voltage circuit of the constant current regulator further includes an operational amplifier for constant voltage, wherein the positive input terminal of the operational amplifier for constant voltage is connected to the positive input terminal of the voltage regulator and to the reference voltage, wherein The negative input terminal is connected to the output terminal of the constant voltage circuit, and its gain output terminal is connected to the gate of the transistor for constant voltage, and a negative feedback circuit is formed by the transistor for constant voltage, wherein the reference voltage It is a bandgap reference voltage, which is used to lock the voltage of the output terminal of the constant voltage circuit, and consume the excess voltage drop to the transistor for constant voltage to stabilize the voltage drop of the light emitting diode group. 26. The drive system according to claim 17, characterized in that: the constant voltage and constant current regulator further comprises: an operational amplifier for constant current, wherein the positive input terminal of the operational amplifier for constant current is connected to the The positive input terminal of the current source is connected to the set voltage, the negative input terminal is connected to the second output terminal of the current source, and the gain output terminal is connected to the negative input terminal to form a negative feedback circuit, and Wherein the reference voltage is a bandgap reference voltage for stably locking the voltage of the second output terminal of the current source, and the voltage of the second output terminal is pressurized to the set resistance to generate A current flowing out of the second output terminal; and a positive carrier channel current mirror, the positive carrier channel current mirror is composed of a pair of common gate positive carrier channel transistors, the drain of one of the positive carrier channel transistors pole is connected with the gate, which is the input terminal of the positive carrier channel current mirror, and the drain of the other positive carrier channel transistor is the output terminal of the positive carrier channel current mirror, and the The input terminal of the positive carrier channel current mirror is connected to the second output terminal of the current source, and the output terminal of the positive carrier channel current mirror is connected to the first output terminal of the current source to replicate The current flowing out of the second output terminal is used to output a reference current. 27. The drive system according to claim 26, characterized in that: said constant voltage and constant current regulator further comprises: a transistor for constant current placed between the second output terminal of said current source and said constant current Between the input terminals of the positive carrier channel current mirror, and between the gain output terminal of the operational amplifier for constant current and the negative input terminal, the connection is cut off, connected to the gate of the transistor for constant current, for strengthening The voltage fluctuation of the second output terminal of the current source is stabilized, and the excess voltage drop in the current source is absorbed. 28. The drive system according to claim 15, characterized in that: said constant voltage and constant current regulator further comprises: a first current mirror, said first current mirror is composed of a pair of common gate transistors , the drain of one of the transistors is connected to the gate, which is the input terminal of the first current mirror, and the drain of the other transistor is the output terminal of the first current mirror, and the first The input end of the current mirror is connected to the first input end of the current sink, connected to the reference current output from the first output end of the current source, and the output end of the first current mirror is connected to the The second input terminal of the current tank is connected to the current from the LED group, and the voltage of the second input terminal of the power supply tank is stabilized through the constant voltage circuit, and at the same time, the first current The mirror uses the reference current Iref output by the current source to lock the light-emitting diode group current ILED amplified by N times the reference current Iref, and the N times value N=ILED/Iref. 29. The drive system according to claim 28, characterized in that: the constant voltage and constant current regulator further comprises: a second current mirror identical to the first current mirror, and the input of the second current mirror The terminal is interposed between the input terminal of the first current mirror and the first input terminal of the current sink, connected to the reference current output from the first output terminal of the current source, and the second current mirror The output end of the first current mirror is interposed between the output end of the first current mirror and the second input end of the current sink, and is connected with the current from the light emitting diode group, and the second current mirror and the second current mirror are connected to the second input end of the current sink. Like a current mirror, the reference current Iref output by the current source is used to lock the light-emitting diode group current ILED amplified by N times the reference current Iref, and the N times value N=ILED/Iref. 30. The driving system according to claim 28, characterized in that: said constant voltage and constant current regulator further comprises: a pair of current sink common gate transistors, placed between said first current mirror and said Between the input terminals of the current sink, a transistor switch is added on the line connected to the gate of the current sink common gate transistor, and the gate voltage of the transistor switch is used to control the switch of the current of the light-emitting diode group , using the gate voltage of the functionalized transistor switch to adjust the flickering frequency of the light-emitting diode group to the expected luminous power. 31. A redundant circuit for use in light emitting diode groups, characterized in that: by detecting that the voltage difference between any two nodes in the light emitting diode group exceeds the starting voltage, the redundant controller is activated to control the The bypass circuit of the two nodes is in a conducting state, so that the current of the LED group can bypass the abnormally operating LED between the two nodes, so as to maintain the normal light emission of the LED group. 32. The redundant circuit according to claim 31, wherein the starting voltage is a fixed voltage. 33. The redundant circuit according to claim 31, wherein the starting voltage is an adjustable voltage. 34. The redundant circuit according to claim 31, characterized in that: the bypass circuit is a silicon-controlled rectification component connected in parallel with the light-emitting diode group, and the gate of the silicon-controlled rectification component is controlled by a redundant The redundant controller is controlled, and when the redundant controller outputs gate current, the silicon controlled rectifier component is turned on so that the light emitting diode current bypasses the abnormally operating light emitting diode. 35. The redundant circuit according to claim 31, characterized in that: said bypass circuit comprises: a first metal oxide semiconductor field effect transistor connected in parallel with the light emitting diode group, and said first metal oxide The gate of the object semiconductor field effect transistor is controlled by the redundant controller, and when the redundant controller outputs the gate current, it turns on the first metal oxide semiconductor field effect transistor so that the light emitting diode current bypasses the abnormally operating light emitting diode. a diode; and a resistor connected to the drain and the gate of the first metal-oxide-semiconductor field-effect transistor for setting the set voltage value of the redundant circuit. 36. The redundant circuit according to claim 35, wherein the bypass circuit further comprises a resistor connected in series with the source of the first metal oxide semiconductor field effect transistor for setting the The voltage difference of the above-mentioned bypass circuit after it is turned on. 37. The redundant circuit according to claim 35, characterized in that: said bypass circuit further comprises a Zener diode connected in series with the source of said first metal-oxide-semiconductor field-effect transistor, for setting Determine the voltage difference of the bypass circuit after it is turned on. 38. The redundant circuit according to claim 35, wherein the bypass circuit further comprises a second MOSFET connected in series with the source of the first MOSFET A field effect transistor, and the gate and drain of the second metal oxide semiconductor field effect transistor are connected for setting the voltage difference of the bypass circuit after it is turned on. 39. The redundant circuit according to claim 31, characterized in that: the bypass circuit comprises: a zener diode connected in parallel with the light emitting diode group, when the voltage at both ends of the bypass circuit is abnormal due to abnormal operation When the light-emitting diode exceeds the set voltage value, the reverse bias current of the Zener diode starts to conduct, so that the light-emitting diode current bypasses the abnormally operating light-emitting diode; and a resistor connected in series with the Zener diode , for setting the set voltage value of the redundant circuit. 40. The redundant circuit according to claim 31, characterized in that: the bypass circuit comprises: a transistor connected in parallel with the light-emitting diode group, and the gate of the transistor is controlled by the redundant controller, when The redundant controller outputs gate current to turn on the transistor so that the light-emitting diode current bypasses the abnormally operating light-emitting diode, and the redundant controller also controls the base current for setting the bypass circuit at a voltage difference after being turned on; and a resistor connected to the drain and the gate of the first MOSFET for setting the set voltage value of the redundant circuit.

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